Telephone system.



E. D. FALES. -TELEPHONE SYSTEM.

APPLICATION FILED MAY 7, 1907.

Patented \0ct. 17, 1916.

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TELEPHONE SYSTEM.

APPLICATION FILED MAYT, 1901 v Patentvd Oct. 17,1916.

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TELEPHONE SYSTEM. APPLICATION FILED. IIIAY 1. I90? Patented Oct. 17, 1916.

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*ofi'icient telephone exchange system in EDWARD D. FALES, OF CHICAGO, ILLINOIS AUTOMATIC ELECTRIC COMPAN TELEPHONE SYSTEM.

Application filed May 7, 1907.

To all 'HILOHL it may concern Be it known that I, EDWARD D. FALEs, a citizen of the United States of America, and resident of Chicago, Cook county, Illinois, have invented a certain new and useful Improvement in Telephone Systems, of which the tolhnving is a specification.

My invention relates to telephone systems in which provision is made for automatically extending either all or a portion of the connection from the calling subscribers line to the called subscribers flline.

(lrenerally stated .the'object of my invention is to provide an improved and highly which provision -is made for automatically selecting trunks or trunk lines or other suitable connections.

Special objects of my invention are the irovision of means by which a step-by-stepoperated line wiper may normally rest upon the terminal of an idl': trunk or line, and whereby the use of this line wiper for talking purposes automatically advances all idle associated line wipers into connection with another idle trunk or line, all idle line wipers being thus normally connected in multiple with an idle trunk or line, which idle trunk or line is preferably the one next inorder after the one last put in use; the provision of an improved arrangement by which a group of subscribers lines may be provided with movable line wipers or terminals, and by which all of said line wipers or terminals may normally be connected in multiple to an idle trunk or line, whereby the use of any subscribers line for talking purposes does not necessitate the removal of the calling sub-- soribefis line wiper or terminal from the trunk or line terminal upon which it was normally resting before the subscriber called; the provision of a group of step-bystep switches having movable line wipers or terminals which are all normally connected in multiple to an idle trunk or line, and a master switch provided with means for normally maintaining a guarding potential for all of said trunks or lines except the one n0rmally engaged by the wipers or terminals of the said switches; and the provision of certain details and features of llllPlOYLll'lGllt and combinations tending to increase the Specification of Letters Patent;

called substation.

ASSIGlYlOR, BY MESNE ASSIGNMEE' '3,- TO Y, A CORPORATIONOF ILLINOIS.

Patented Got. 1'7, 1916. Serial No. 372,383.

tor switch 1 and a line switch C allotted to the line of substationA, which latter is the. A ringer generator is shown at I, and at J is indicated a busy-signaling machine. Fig. 3 is a diagrammatic perspective view of one of my improved line ,65 At E is shown or subscribers individual switches. Fig. 4 1s a 'diagranmiatic perspectii'e View of the said group-switch. Figs. 5, 6, 7, 8, 9, 10 and 1 1 are detail views of the substation impulse springs, showing the various positionsbf the same. i i i The substations may be of any suitable or approved type. with which I have elected to illustrate my invention comprise a receiver 2, a switchhook 3 for controlling the substation circuits, which controlling operations are accomplished through the medium of any suitable means, such as the can'i-arms 4i, 5 and 6, as indicated. As the switch-hook is lowered the cam-arm 4 momentarily presses the release springs 7, Sand 9 into engagement,

Those. in connection whereby the substation line conductors may 7 be grounded sin'iultaneo'usly. When the switch-hook is do\vn tli e y;am:arm 5 engages the groumlsprings 18 and 19 by the camcircuit is normally broken between farm s; but when said springsare together, ground is then provided to the ground post an automatic substation, it is provided with the, usual vertical and rotary impulse springs 23 and 24, for the. purpose described. The vertical impulse spring 23 is provided with an oblique projection or lug 192 on its un- 'derside, with which the vertical impulse teeth 29 are adapted to engage for driving the spring 23 intermittently onto the ground post (Fig. 5) to ground the line. The rotary impulse spring 24 is provided with A somewhatsimilar mechanism for driving the said rotary spring 24 onto the ground. post once when the dial is rotated in one direction, and once when the dial is rotated in the opposite direction. The said rotary mplulse spring 24 has on its under side a -s aped member 193 having two sides 0 and d,and there is, in addition, an auxiliary spring 194 which works in conjunction with said V-shaped member. clearlyin Fig. 5, the auxiliary spring 194 is provided with a lower curved part c having the rear section 195 curving outwardly, as shown also in Figs. 5 to 10, inclusive. The front section 196 of said member 6 is designed to fall just below the apex of the .V-shaped member 193, so that the rotary impulse tooth 30, when, moved in the direction of the arrow (Fig. 6), willpass onto I the curved member e, thus pressing the rotary impulse spring 24 onto the ground post 20 for a comparatively long time (see Fig. 7), and sending to the line a comparatively long ground impulse. As the impulse wheel advances, the vertical impulse teeth 29 approach the lug 192 of the vertical impulse spring 23 (Fig. 7), and eventually the first tooth 7 that meets the lug 192 clears the said lug, as shown in Fig. 8, but not until after the rotary impulse tooth 30 clears the curved member (2 in the manner illustrated. As the impulse wheel continues to advance in the direction of the arrow. (Fig. 8), the next impulse tooth will clear the projection 192, as shown in Fig. 9. Then when the impulse Wheel is released the vertical impulse spring 23 is twice carried into engagement with the ground 'post-20, in themanner indicated in Fig. 10; but'as the impulse Wheel nears its normal position the rotary impulse tooth 30 passes under the curved member e 01: the auxiliary spring 194. (Fig. 11) engaging the V-shaped member 193' directly and for a short time only, and sending to the line the ordinary impulse through the medium of the rotary impulse spring 24, after which the said member 193 is clearedor disengaged as the impulse wheel reaches its nor- As shown more mal position, as shown in Fig. 6. The operations as thus described are repeated each time that the dial is operated, and the nunr ber of impulses provided through the medium of the vertical impulse spring 23 are accurately and definitely determined at each the vertical impulse teeth 29 and the rotary impulse tooth 30 are carried on. the periph ery of the so-called impulse wheel 28, said wheel being rigidly secured to the shaft 25 in the well-known manner. With the equipment thus described the subscribers vertical line conductor 31 may first be given a number of ground impulses, and then the rotary line conductor 32 is given one ground impulse. It will be noticed that as long as the dial is out of normal position the construction is such that the dog 26 permitsthe primary circuit springs 33 and 34 to separate, thus preventing the impulses that are delivered to either line conductor from passing to the other.

The means whereby the subscriber may signal the called subscriber comprises the push-button spring 35 which normally engages the contact point 36; but when the button 37 is pressed the spring 35 engages the contact point 38, ,whereby the vertical line conductor 31 maybe grounded.

e As shown in Fig. 3, the line switch C comprises the private magnet 39 which, through the medium of the escapement springs 40, permits the side switch K to pass from first to, second position. The side switch K comprises the side switch wipers 41, 42, 43 and 44 which may be termed the vertical, rotary and private side switch wipers, and the ro tary magnet side switch wiper, respectively. *The operation of the private magnet 39 and the side switch K is similar to the operation of the private magnet and side switch of the selector switch disclosed in United States Letters Patent No. 815,321, granted March 13, 1906, to Keith, Erickson and Erickson. The rotary magnet 45, when energized, oper ates to carry the shaft 46in a rotary or circular direction. .The shaft 46 is provided with the hub 47 which has longitudinal teeth around its circumference. These teeth are adapted to.be engaged by the pawl 48 upon the endof the armature 49- to rotate the shaft. The wipers 49, 50 and .51 mounted upon the lower end of the shaft 46' may be 1 side switch wiper designated as the vertical, rotary and private shaft Wipers, respectively, and are adapted to have sliding electrical contact with the brushes 52, 53 and 54, respectively. Furthermore, the wipers 49,, and 51 have their arms arranged at an angle of about one hundred and twenty degrees, so that Whenever one arm engages the first contact, as sl1oWn,,a second arm has just passed out of engagement with the tenth contact (Fig. 3) and is in the position where the eleventh contact would be found. The release magnet 55 is provided for restoring the side switch K to normal position. When the magnet 55 energizes, the armature 56 is attracted, whereby the member 57 is pressed to the left. This member 57 in turn'prcsses the link 58, which engagesthe 'arm 59, thus rotating the side switch K about the pivot points 60, restoring the side switch from second to first position. When the member 57 is operated the tip 61 carries the spring 62 out of engagement with the spring 63 and into engagement with the spring 64. By this operation of the spring 62 the conductor 65, leading from the'contact point 66 of the 12, is shifted from connection with the private magnet 39 to connection with the release magnet 55. The cutoff relay 67 is provided for disconnecting the private magnet 39 from the subscribers rotary line conductor when a connector calls in on the line. The relays 68 and 69 are so arranged that when both are energized simultaneously the springs 70 and 71 are pressed into contact, thereby closing an energizing circuit through the release magnet 55, for the purpose explained. It will be seen that across the terminals of the relays 08 and 69 are bridged the. condensers 72 and 73, respeetively.

The gro'ip-switch D (Fig. 41) comprises a rotary :lnagnet 74-, with the usual interrupter springs 7 5; and when the magnet 74 is energized the armature 7 6 is attracted, whereby the pawl 77 is carried into engagement with the hub 7 8, whereby the shaft 79 is rotated. Upon the shaft are mounted the wipers 80 and 81 which are adapted to engage their respective banks. Upon the ends of the wiper 81 are carried insulating bushings 82 which, as the wiper passes over the bank, carries the ground spring 83 out of contact with its associated segment 8-1, as shown. The operating magnet 71 is maintained in electrical connection with the wiper 80 by means of the brush 85, as illustrated.

The first-selector switch E (Fig. 1) is the same as the selector switch disclosed in said selector patent, with the exception that there are no normal conductors. There is also, of course, no necessity in the selector switch E for a bridge-cut-off relay, and it is also omitted, and the line relays 108 and 109 are connected directly to the battery 107 to make and break the circuit.

lead. The private normal conductor is of no use in connection with the selector switch E, and is also omitted. Since like parts are likewise represented through out the drawings, the vertical-magnet 9(3 and the rotary magnet 97, the release magnet 98 and the private magnet 99 will The vertical movement of the switch shaft,

and, therefore, of the wipers 119, 120 and 121, is controlled by the vertical magnet, and the rotary movement by the rotary magnet 97, the rotary magnet circiiit being provided with the usual interrupter springs The operative nragnets of the switch are, of course, controlled by' the subsr -.ribcr through the medium of the vertical and rotary line relays 10S and 109, as is well known. Said relays have under their controlthe usual sprii'igs 1.10, 111 and 112 for controlling the local circuits. -By means of the back-release relay 115 the release of the switch E is brought about after the side switch has passed to third position.

The connector switch I is of the general type described in United States Letters fllatent No. 815,176, granted March 13, 1900, to -Keith, Erickson and Erickson. The mechanical details of the first-selector and connector, as is well known, are very much the same. The connector switch shaft (not shown), like the first-selector switch. shaft,

carries the line wipers 125 and 120 and the private wiper 127. The connector switch is also controlled by the calling subscriber through the medium of the vertical and 1'0- tary line relays 128 and 129, as explained. The vertical line relay 128 directly controls the vertical magnet 130 and also the rotary magnet 131 and the ringer relay 132, for the well-known purposes. The oliice of the vertical magnet-130is to give the shaft and shaft jwip'ers their vertical motion, and the rotary magnet 131 imparts to the shaft and shaft wipers a rotary or circular motion. The rotary line relay controls the private magnet 133 which, under certain conditions, in turn controls the vertical and rotary magnets 130 and 131, the release magnet 134, and also the side switch wipers 135, 1.30, 137 and 138, to'change the circuits. The side switch of the connector, like the side switch of the first-selector, has a normal'or first position, a second position and a third position. The release magnet 134: is also controlled by the line relays 128 and 129 conjointly. By the condensers 1 1-0 and 141 the circuit through the connector is divided into two sections. The back-bridge relays 142 and 143 constitute means whereby the called subscriber may release the connector switch that has been connected with his line.

A'clearer understanding of my improved system may be obtained i'rom an explanation of the operation by which one subto ground G, as shown.

scriber calls another. .Assuming, for example, that the subscriber at substation A desires to call the subscriber at substation A, to which is allotted the line #220, the mode of operation is as follows: To call the number 220 tl 1e subscriber at substation A operates his calling device once, in the well known manner, for each digit. The preliminary impulse for operating the line switch C occurs when the calling subscriber rotates the dial forward for the first digit, whereby the rotary impulse spring 24 is momentarily pressed against the ground post 20 to ground the line. As a result the private magnet 39 of the line switch C is energized by a flow of current from ground G to the springs 18 and 19, ground post 20, impulse spring 24 to the rotary line conductor 32, side switch wiper 42, contact point 66, cut-oil relay springs 144 and 145, release magnet springs 62 and 63, magnet 39, thence through said private magnet to the battery lead 148, thence through batteryB As soon as the private magnet energizes and deenergizes, the side switch passes from first to second position, whereby when the side switch wipers 41 and 42 engage the contact points 149 and 150, respectively, the subscribers line conductors 31 and 32 are extended to the shaft wipers 49 and .50, respectively, which are in engagement with the contact terminals of a trunk line leading to the firstselector E (Fig. 1). When the side switch wiper 44 engages the grounded contact point 151 a protecting or guarding ground potential is established at the contact point engaged by the private wiper 51. This po tentialprotects the engaged trunk line from seizure by other individual switches. Furthermore, this guarding potential sends an energizing current through the rotary magnet 152 of the individual switch L of the same group of which the switch C is a member. An energizing circuit. is also established through the rotary magnet 74 of the group-switch D, as illustrated. The circuit through the rotary magnet 74 of the groupswitch D extends from ground G to the contact point 151, side switch wiper 44, brush 54, private wiper 51 to the contact 153, thence to the conductor 154, contact point 160 on which the private wiper is resting (see Fig. 4), thence to the private wiper 80, crush 85, interrupter springs 75, rotary magnet 74 to the battery lead 148, and through battery B to ground G, as

shown. The rotary magnet 74, upon energizing, operates to rotate the shaft, so that the wipers 80 and 81 are advanced one step, as shown in Fig. 1. The wiper 81 is adjusted slightly in advance of the wiper 80 that is, the bushing 82 is so arranged that the springs 83 and 84 are carried out of engagement before the wiper 80 engages the next contact point. /Vhen the springs 83 and 84 disengage, the normal ground poten tial from ground G is removed from all of the second private bank contacts of the line or individual switches allotted to the switch D, such as the contact 159 of the switch L, for example. The circuit through the rotary magnet 152 of the individual switch L extends from ground G to the contact 54, shaft wiper 51, contact point 153, con:

ductor 154 to the contact point 155, shaft wiper 156, side switch wiper 157, through the interrupter springs 15S, and through the rotary magnet 152 to the battery 13 and to ground Ur, as shown. The rotary magnet 152, upon energizing, operates to rotate the shaft wipers of the individual switch L to the next set of idle contact points which, for the private wiper 156, is the contact point 159, as illustrated. Not only is the switch L thus operated, but also all idle switches of the same group, similar to the switch L, are likewise operated, and the shaft wipers of each switch are carried into contact with the multiple contacts of the same trunk line. Now, if the switch L were operated by its subscriber exactly as the switch (3 has been operated, its side switch will also be tripped, whereby a ground potential is established at all second private bank contacts, so that the 'roup switch D and all individual switches rest ing on this contact are again moved one step to the next contact, and so on.

Returning again to the operation of the switch (1 it will be seen that when the side switch wipers 41 and 42 engage the contact points 149 and 150, respectively, the subscribers line conductors 31 and are e:'- tended to the trunk conductors and 161, respectively, which lead to the selector switch E, as explained. The first digit be ing 2, the subscriber operates his dial accordingly, grounding the vertical line conductor 31 each time that the spring 23 is pressed onto the ground post 20,, and the rotary line conductor 32 once when the rotary impulse spring 24 is pressed onto the ground post 20. As a result the vertical line relay 108 of the first-selector E is energizedby a flow of current from the substation ground; G through shaft wiper 49, vertical trunk conductor 160, 1.

switch wiper 100 of the selectorE, contact point 162, vertical line relay 108 to the battery lead 148, thence through battery B and to ground G energizing the line relay. Each time that the said vertical line relay 10S energizes, the line relay spring 111 is pressed onto the ground spring 110, closing the local circuit. The vertical magnet 96 is thereby energized, and the wipers 119, 120 and 121 of the selector E are raised to the second bank level -and brought opposite the first contact of said level. The energizing circuit of the said vertical magnet 96 extends from ground G through the springs 110 and 111, private springs 105 and 106 to the vertical magnet 90, thence to the battery lead 148, and through battery B to said ground. The spring 24 is then pressed onto the ground post 20, grounding the rotary line conductor and energizing, therefore, the rotary line relay 109 of the selector E, thus closing a local circuit. The energizing current passes from ground G to the rotary line conductor Thence it flows through the side switch wiper 42, contact point 150, rolay 09, brush 53, shaft wiper to the rotary trunk conductor 101, side switch wiper 101 of the selector l9, contact point 103 to the rotary line relay 109, thence to the battery lead 148, and through the battery B to said ground. The rotary line relay, upon operating, presses the line relay spring 112 onto the ground spring 110, thereby establishing a circuit through the private magnet 99 from ground G through the springs 110 and 112 to the private magnet 99. and through the said magnet to battery lead 148, thence through battery T3 to ground. The private magnet. upon energizing and dei nergizing, peri'uits the selector side switch to pass from first to second position. permitting the side switch wipers 102 and 103 to engage the contact points 101 and 10S. res wctively. The closure of conne tion bet ween the side. switch wiper 102 and the contact point 101 sets up an energizing circuit for the rotarymagnet 97 from ground (1 to the contact point 101, thri'iugh the side switch wiper 102. inlcrrupter'spring 107. rotary magnet 07 lo the battery lead HR. and then through battery l3 to said ground G. as illustrated. The said rotary magnet. 97 then operates to rotate the wipcrs ll9, 120 and 121 ol' the selector 1', into engagement with a trunk line leading-to some idle connector switch, and, in the particular case underconsideration, to the connector switch 1 in order to extend the con 1 ueclion. 11 the .wipers have to pass over busy trunk lines then as soon as the private wiper 121 engages a grounded contact point [be private magnet energizes again, l(1('l\'- ing lhe sidiswitch in second position. The energizing circuit l'or said private magnet extends from the grounded terminal (1 of battery It through an occupying switch side switch wiper 102 in engagement with the contact point 104, whereby the rotary magnet 97 will be energized step by step until the wipers are carried beyond the last busy trunk line. At the instant that the private wiper leaves the last busy contact point the energizing circuit through the private magnet 99 is destroyed, and as a result the selector side switch passes to third position. If, however, there are no busy trunk lines, the rotary magnet 97 releases the side switch to third position as soon as the wipers are carried into engagement with the first trunk line. As soon as the side switch passes to third position, as stated, the subscribers line conductors 31 and are extended to the conductors 107 and 108, which in this case, it is assumed, lead to the connector switch F, as shown The extension of the line connection occurs, of course, as soon as the side i switch wipers 100 and 101 engage the contact points 1.09 and 170, respectively. Not only is the subscribefs line thus extended, but a guarding potential is also established at the private wiper 121, when the side switch wiper 103 passes onto the ground con-' tact point 171, tor protecting the seized trunk line against interference by other calling subscribers. This guarding potential is established from ground (i to the contact point 171, thence through the side switch wiper 103 and through the back-release re- 105 lay 113. conductor 100 to the private wiper 121, as illustrated.

It will, of course, be necessary that the energizing circuit for the rotary magnet 97, to which reference has already been made, be destroyed when the idle trunk line is seized. This occurs when the side switch wiper 102 leaves the contact point 104. The ground impulses l'rom the substation to-the line conductors lor the last two digits are ell'ective. in operating the connector 1* to further extend the. connection. For the second digit 2 the vertical impulsev spring 23 is pressed onto the ground post 20 twice, and the. rotary impulse spring 24- is pressed onto the ground post once, whereby an energizing circuit is closed through the connector vertical and rota rv line relays 128 and 129, clos- I ing local circuits. The circuit through the' vertical line relay extends 'l 'rom ground G through the ground post 20, spring 23, line conductor 31. side switch wiper 11. shaft wiper (l9. tl'llll-h' conductors 100 and 107, vertical line relay 1% lo the battery lead 1 1%,

thence throughbattery 15 to ground. Each 110 :#:220. Following the vertical impulses the rotary impulse spring 2% makes contact with the" ground post 20, thereby closing an energizing clrcuit through the rotary l1ne relay 129 extending from ground (l through the ground post 20 and spring 2l, line conductor 32, trunk conductors 161 and 168, through the rotary line relay 129 to the battery lead H8, thence through battery B to ground G, as shown. The rotary line relay upon operating closes an energizing circuit through the private magnet 133 which operates in turn to release the connector side switch from first to second position. The energizing circuit through the private mag net 133 is established when the rotary line relay 129 presses the spring 114: onto the ground spring 173, at which time the energizing current flows from ground through the private magnet 133, causing the said connector side switch to' trip from first to second position. The last digit being naught, the calling device is operated. as previously described. grounding the vertical line conductor 31 ten times and the rotary line conductor 32 once. The vertical and rotary line relays 128 and 129 are operated over previously traced circuits. However, when theline relay springs 172 and 173 engage, a circuit is closed through the rotary magnet 131, instead of through the vertical magnet 130, to energize the former. Each time that the rotary magnet is energized it operates to rotate the shaft and shaft wipers 126 and 127 one step at a time until the said wipers are carried into engagement with the normal conductors 174, 175 and 176, the former two of which lead to the line terminals of the desired substation. The energizing of the rotary line relay 129, .as previously stated, completes an energizing 'circuit through the private magnet 133, which now operates to release the side switch from second to third position, thus placing the side switch wipers 135, 136, 137 and 138 in contact with their respective contact points. Furthermore,

' when the side switch wiper 138 engages the contact point 177, a guarding potential is established for protecting the called line. This potential extends from ground G to the contact point 177, side switch wiper 138, and to the private wiper 127 which en; gages the private contact of the called line.

I The said engagement of the side switch wiper 138 and contact point 177 also closes an energizing circuit through the cut-ofiz' relay 178 of the line switch C, as illustrated. This circuit extends from ground G to the side switch wiper 138, shaft wiper 127, side switch wiper 182 of theiswitch C, through the cut-off relay 178 to the battery lead 1-18, and through battery B to ground. The relay 178, upon energizing, operates to disengage the springs 183 and 184, whereby the private magnet 185 is disconnected from the rotary line conductor 180, explained. The line conductors179 and 180 of the substation are now connected to the calling substation. To signal the called subscriber, the calling subscriber presses the button 37, whereby the spring 35 is pressed into engagement with the ground spring 38, whereby an energizing circuit is established through the connector vertical line'relay 128, closing a local circuit. now operates to close an energizing circuit through the ringer relay 132 which operates in the usual manner to bridge the ringer generator I across the line conductors 179 and 180 to operate the ringer 181 at the sub station A, to-signal the called subscriber.

The said relay 128 The subscriber at substation A upon removing the receiver 186 from the switchhook 187 may converse with the subscriber at substation A over the circuit shown by the heavy lines in Figs. 1 and 2-that is, over the talking circuit.

The release of the central office switching apparatus occurs when the calling subscriber restores the receiver 2 to the switch-hook 3, thereby pressing the release springs 7, 8 and 9 into engagement for a moment, and thus grounding the line. The contact of the said release springs grounds the vertical and rotary line conductors 31 and 32 simultaneously from ground G to the release spring 7. thence through the springs 8 and 9 to the vertical and rotary line conductors, thereby simultaneously energizing the line switch relays 68 and 69, and the vertical and rotary line relays 128 and 129 of the connector F, whereby the release relay 115 of the selector 1) is ener ized in series with the P" release magnet 13l of the connector F, releasing the switches. The path of the series circuit through the release relay 115 and releasefl nagnet 134 extends from ground G to the side switch wiper 103, release relay 115, selector shaft wiper 121, release springs 188 and 189, release magnet 134to the battery lead 148, thence through battery B to ground (l, as shown. When the connector release magnet 134 is thus supplied with current it energizes, and as a result the switch shaft and side switch are restored to normal position, thus breaking the connection between the connector switch shaft wipers 125, 126 and 127 and the normal conductors 174:, 175 and 176, to release the connector. The back-release relay 115 of the selector E, being in the same circuit with the release magnet 1.3-1, energizes simultaneously with the latter and presses the springs 190 and 191 into engagement..which .in turn close an energizing circuit through the release magnet 08 of the first-selector E, re-

leasing the latter. This circuit extends from ground (i through the release relay springs 190 and 191, through the winding of the release magnet 98 to the battery lead 148, thence through battery P) to grountil (l, as illustrated. The energizing circuit hrough the release relay 115 is maintainedi iisjlong as the connector vertical and rotary line relays are energized simultaneously, Vhen the connector line relays 128 and 129 deenergize, the energizing circuit through the release relay 115 is broken. and therelease magnet 98 of the selector E deenergizes'. irestoring the selector shaft wipers and side switch wipers to normal position. The line switch relays GR and 9 upon energizing simultaneously press into contact the springs and 71, whereby an energizing circuit is established through the release magnet 55 of the individual or line switch C, said circuit extending from ground G through the springs 71 and 70, release magnet 55 to the. lead 148. and through battery 13 to ba tterv ground G. giving a flow of battery current. The release magnet upon energizing attracts its armature 56 which operates. as previously explained, to restore the side switchto first position. \Vhen the release magnet 55 operates, the spring 2 is then carried out of engagement with the spring 63 into engagement with the spring 64. Now, when the side switch wiper 42 returns to first position a new energizing circuitis established through the release magnet 55, said circuit extending from\the grounded rotary line conductor 32 through the side switch wiper 42, contact point 66.. through the cut-off relay springs 144 and H5. springs 62 and (3-1 to the release magnet 55, thence to the battery lead 14S. and through battery B to ground (it. as illustrated. The energizing circuit through the release magnet is broken when the release springs 7, S and 9 disengage, thereby removing the ground from the vertical and rotary line conductors 31 and 32 and restoring them to normal condition. The calling subscriber tlms'restores allthe switching apparatus which he brought into use. \Vhen the, side switch' wipers 4-1 and 42 pass from second to first position the energizing circuits through the connector vertical and rotary lino relays 128 and 129 are broken. Furthermorc. when the side switch wiper 41 returns to first position the rotary magnet 15 is restored to normal connection with the shaft wiper 51, as shown.

It has been explained. how all the private bank contacts of the line switches C, L, etc.,

are normally grounded at the master or controlling switch D, except one, so as to make it impossible for any of the line switches (l, L, etc., to rest (while the side switch is in :normal position) with their line wipers in engagement with any bank contact, except the one that is left uncovered or unguarded by the bushing 82 of the master switch D. It will therefore be evident that if, after tl line switch C has seized the trunk line le ih ling from the first set oil contacts, as si in Fig. 1, and it subsequently and before the switch C is released two other, subscribers of the same group with the subscriber make a call, the master switch D will then be advanced two steps and caused to rest with these wipers on the fourth contact, It will be evident. therelfore, that the unig uarded or unprotected COjflttlCt in that event will be this fourth contact. Therefore, if the subscriber-.\ releases when the master switch I) is at this point, the rotary magnet 15 of the line switch (1 being thrown into connection with the private wiper 51, as alioiivn ready explained. will become eneigized by a low of currcnt'from ground G at the master snitch l) to the first master switch contact. thence to the first private bank contact of the line switch private wiper 51, brush 51,

side switch wiper ll. and through the interrupteu springs of the rotary magnet i5, thence through said rotary magnet to the battery lead 1-18. and through battery B to ground (l. as shown. The rotary magnet will operate to advance the shaft wipers, and among them. of course, the private wiper 51. onto the second contact. Again 'the energizing circuit will' be established through the rotary magnet -15, which will carry the wipers onto the next or third contact. and finally the rotary magnet 45 is energized once more and the wipers are carried onto the fourth contact, which latter contact being unprotectedthat is, disconnccted from ground G". or from any other ground conncctionthe circuit through the rotary magnet -15 is broken and the wipers caused to come to rest on this trunk. Of course. when any other subscriber 'alls after the switch has come to rest the line switch of the calling subscriber will then put ground on this fourth contact, driving all other switches of the group, including the master switch 1). onto the next contact. if the said next contact is not in use. However. if the said contact is in use it will be impossible for.lhc master switch I) to reniove the ground connection maintained by .lhc linc switch that is monopolizing this conbe released, including the line switch, which line switch will then operate and put itself in connection with the idle trunk held uncovered by the master switch.

From the foregoing it will be seen that I provide a group of subscribers lines with movable line wipers or terminals which are all normally connected in multiple to an idle trunk or line. Consequently, when a subscriber calls, his line wipers are not advanced or disturbed in any manner whatever, but are allowed to remain in engagement with the idle trunk or line. In this way the trunks or lines are selected ahead of the calls, each calling subscriber being given a preselected idle trunk or line, and at the same time automatically selecting another idle trunk or line for the next callthat is to say, for use by the subscriber who makes the next call. With my improved arrangement the group of subscribers lines are not normally connected with the preselected or waiting trunk line, but are normally disconnected therefrom, notwithstanding the fact that the step-by-step-operated line wipers allotted to the subscribers lines are normally connected in multiple to the preselected idle trunk line. However, as soon as a calling subscriber automatically closes connection between his line and his allotted line wipers, then the line wipers of all other subscribers in the same group are immediately and automatically driven oil from the trunk line upon which they were all resting, and are advanced into connection with the idle trunk line next in order after the one last put in use. lVith such arrangement line wipers or". the subscribers lines always rotate in one and the same directionthat is to say, do not rotate in a forward and back direction, and consequently the trunk line which any calling subscriber uses is always the first idle trunk line next in order after the, one last put in use. This mode of operation tends to simplify and increase the speed with which connections are made, with apparatus of this kind, as the connection of a calling subscribers line to an idle trunk line does not wait upon the automatic selection of such line, and does not wait upon the step-by-step advancement of any line wipe-r orother similar element to select an idle trunk. In other words, the sul'iscribers line terminal is already inengagement with the previously selected idle trunk line, and

all that is necessary is for the subscriber in.

:-;tarting to make a call to automatically close connection between his line and the said line terminal, thus immediately seizing the trunk line with which his individual line switch was already in connection. The step-l ystep operations of the subscribers line switches, to select and connect with idle trunks, are of such character that each subscriber only operates the shaft wipers of the other submatically advances the shaft wipers of all.

idle subscribers line switches inthe same group, but leaves his own shaft wipers exactly where they were before he called, simply closing connection between his line and the said shaft wipers. The effect of the long impulse on the forward movement of the dial is to ground the rotary line and, therefore, to energize the rotary line relay of the connector, which in turn operates to close an energizing circuit through the private magnet, but the operation of the private magnet at this stage of the call is without eil'ect, since the side switch is retained locked in the first position until the switch shaft is given a vertical step.

'hat I claim as my invention is 1- 1. A telephone system comprising a group of subscribers lines, traveling terminals for said subscriberslines, and an idle line to which said terminals are all normally connected in multiple.

2. A telephone system comprising a group of subscribers lines, traveling terminals for said subscribers lines, and an idle trunk to which said terminals are all normally connected in multiple.

3. A telephone system comprising a group of subscribers lines, a step-bystep-actuated line wiper for each subscribers line, an idle line, and as many multiple terminals for said idle line as there are subscribers lines, each line wiper normally engaging one of the tern'iinals of said idle line,

4. A telephone system comprising a group of'subseribers lines, a step-bystep-actuated line wiper for each subscribers line, an idle trunk, and as many multiple terminals for sai d idle trunk as there are subscribers lines,

each line wiper normally engaging one of the terminals of said idle trunk.

5. A telephone system comprising a group of lines. traveling terminals for said lines, and an idle line to which said terminals are all normally connected in multiple.

(3. A telephone system comprising a group of lines, traveling tcrn'iinals for said lines, and an idle trunk to which said terminals are all normally connected in n'sultiple.

7. A tele )hone'system comprising a group of lines, a step-by-stc]i-actuated line \vlper for each line, an idle line, and as many multiple terminals for said idle line as there are lines in said group, each line wiper normally engaging oncol the terminals of said idle line.

8. A telephone systcn'i com -irising a group ol lines, a step-|)y-step-actuated line wiper for each line, an idle trunk, and as many multiple terminals for said idle trunk as there are lines in said group, each line wiper normally engaging one of the terminals oi. said idle trunk.

.nals of said idle trunk,

9. A telephone system comprising a group of subscribers lines, movable terminals for said subscribers lines, and an idle line to which said terminals are all normally connected in multiple, said movable terminals being normally disconnected from the said group of lines.

10. A telephone system comprising a group of subscribers lines, movable terminals for said subscribers" lines, and anidle trunk to which said terminals are all nor- 12. A telephone system comprising a group of subscribers lines, actuated line wiper line, an idle trunk, terminals for Subscribers lines, each line wiper normally engaging one of the terminals of said idle a step-by-stepand as many multiple trunk, and said wipers being normally disconnected from the said group of lines.

13. A telephone system comprising group of lines, movable terminals for said lines, and an idle line to which said terminals are all normally connected in multiple, said movable terminals being normally disconnected from the said group of lines.

14. A telephone system comprising a group of lines, movable terminals for said lines, and an idle trunk to'which said terminals are all normally connected fromthe said group of lines;

15. A telephone system comprising a group of lines, a stop-by-step-actuated line wiper for each line an idle line, and as many multiple terminals for said idle line as there are lines in said group, each line wiper normally engaging one of the terminals of said idle line and said wipers being normally disconnected from the said group of lines.

16. A telephone system comprising a group of lines, a stcp-bv-step-actuated line wiper for each line, an idle trunk, and as many multiple terminalsfor said idle trunk as there are lines in said group, each line wiper normally engaging one of the termiand said wipers be ing normally disconnected from the said group of lines.

17; A telephone system comprising a group of subscribers lines,

movable termisaid idle line as there are sub-.

' .line, an idle line, as many for each subscriberssaid idle trunk as there are.

line, an idle trunk, as

connected in multiple, said movable terminals being normally disnals for said subscribers lines, an idle line to which said terminals are all normally connected in multiple, v nals being normally disconnected from the said group of lines, and automatic auxiliary switches for closing connection between the lines of said group and their movable line terminals.

l8.iA telephone system comprising a group of subscribers lines, movable termir als for said subscribers lines, an idle trunk to which said terminals are all normally connected in multiple, said mo *a-ble terminails being normally disconnected from the said group of lines, and automatic auxiliary switches for closing connection between the lines of said group and their respective movable line terminals.

19.- A telephone system comprising a) group of subscribers lines, a step-by-ste each subscribers multiple terminals actuated line wiper for for said idle line as there are subscribers lines, of the ternnna-ls of said idle line, and said Wipers being normally disconnected from said movable termi,

each line wiper normally engaging one respective the said group of lines, and automatic auxiliary switches for closing connection between the lines of said group and their respective wipers.

20; A telephone system comprising' a" group of subscribers lines, a stcp-by-stepactuated line Wiper for each subscribers nals for said idle trunk as there are subscribers llnes, each llne wiper normally en a 111 one of the terminals of said idle b 33' many multiple termitrunk, and said wipers being normally dis connected from the said group of lines, and

automatic auxiliary switches for connection between the lines of said and their respective Wipers.

closing group 21. A telephone system comprising agroup of lines, movable terminals for said lines, an idle line to which said terminals are all normally connected in multiple, said movable terminals being normally disconnected from the said group tomatic auxiliary switches-for closing connection between the lines of said group and their respective movable line terminals.

22. A telephone system comprising a group of lines, movable terminals for said lines, an idle trunk to which said terminals are all normally connected in multig. said movable terminals being normally disconof lines, and aunected from'the said group of lines, and au tomatic auxiliary switches for closing connection between the lines of said group and their respective movable linet'erminals.

23. A telephone system comprising a group of lines, a step-by-step-actuated line Wiper for each line, an idle line, as many multiple terminals for said idle line as there are lines in said group, each line Wiper nor 'mally disconnected from the said group of lines, and automatic auxiliary switches for closing connection between the lines of sa1d :group and their respective wipers.

A telephone system ;comprising a group of trunk lines for talking purposes, a step-by-step-operated line wiper normally connected with one of said trunk lines, and automatic means for advancing said wiper into connection with another trunk line when the said trunk line with whiclrit is normally connected is put in use for talking purposes. A

26. A telephone system comprising a group of trunk lines, multiple terminals for said trunk lines arranged in banks, a line wiper for each bank of trunk line terminals, said wipers all normally engaging multiple terminals of the same trunk line, and automatic means for advancing all idle Wipers to another trunk line whenever one wiper is used for talking purposes.

27. In a telephone system, the combination of a plurality of trunk lines a plurality of subscribers lines, terminals for the subscribers lines, and automatic means by which any calling subscriber connects the terminals of all idle subscribers lines in multiple to an idle trunk line.

28. In a telephone system, the combination of subscribers lines, a group of trunks less in number than the subscribers lines, movable terminals for the subscribers lines, automatic means by which any calling subscriber connects the movable terminals of all idle subscribers lines in multiple with an idle trunk line, and automatic means by which the calling subscriber closes connection between his line and his allotted line terminal.

29. In a telephone system, the combina tion of one group of lines, another group of lines, movable line terminals for the first group of lines, and automatic means for connecting all idle line'terminals in multiple to an idle member of said second group of lines when a member of the first group of lines is in use by a calling subscriber.

30. A telephone system comprising subscribers lines, a line switch for each subscriber, trunk lines common to a group of line switches, a contact. for each trunk line allotted to eacn line switch, wipers for each line switch adapted to engage the said con tacts, automatic means for normally maintaining the wipers of all idle line switches in engagement with the multiple contact oil an idle trunk line, and means by which a calling subscribers line connected to the idle trunk line without operating the wipers of the line switch allotted to the calling subscriber.

31. In a telephone system, a subscriber's telephone, a line switch, a line terminating in said telephone at the subscribefis station, and in said line switch at a central station, a side switch allotted to said line switch, a private magnet for controlling said sideswitch, means at the subscribens station for sending a preliminary impulse for energize ing the said private magnet, a trunk line terminating in said line switch, a. set of contacts for said trunk line, and wipers for said line switch normally in engagement with i said trunk line, whereby when the subscriber sends in a preliminary impulse the private magnet is operated and the side switch tripped and the line switch wipers and trunk line connected to the subscribers line.

A telephone system comprising a plurality of. subscribers lines, a line switch for each line, a plurality of trunk lines common to all of the switches, means whereby all ere ccpt one of said trunk lines are mn'mally maintained with guarding potential, means whereby all line switches are normally in connection with the unguarded trunk line, meanswhcre'by it a line switch is operated the said unguarded trunk line is seized and made busy and the next idle trunk line dc prived of guarding potential and all idle line switches advanced to the said next idle line.

33. A telephone system comprising a plurality oi subscribers lines, a line switch for each line, a plurality of trunk lines common to all of the switches, a master switch allotted to said line switches, means'u-hcrcby all except one of the said trunk lines are normally maintained with guarding potential by the said master switch, means whereby all liue switches are normally in connection with the unguarded trunk line, means whereby it a line switch is operated the unguarded trunk llne is made busy by the said calling line switch and the next idle trunk means whereby normally, all the private wipers maintained in connection with I iii the same line, and automatic means whereby one line switch may operate all the other line switches to cause their private wipers to be shifted whiletheir side switches remain in first position.

35. In a telephone system, a plurality of trunks,.a trunk selector switch, a private magnet, and a release magnet for switching the line from the private magnet to the release'magnet, as set forth.

.36. In a telephone system, a plurality of trunks, a trunk selector switch provided with a'cut-off relay, a release magnet, a private magnet, and an energizing circuit for said private magnet controlled by the said cut-off relay and said release magnet.

; 3,7, In a telephonesystem, a rotary switch 'provided with a release magpet, an energiz- .ing circuit for said release magnet, releasing relays, a subscribers telephone, a plurality I of energizing circuits for the release magnet,

one of which circuits is directly controlled by the said release relays, another of which circuits is directly controlled by the subscribers telephone, and both of which circuits are controlled by the release magnet itself.

38. In a telephone system, a master switch provided with a rotary switch shaft, a rotary magnet, a multiple terminal wiper provided with three engaging arms for controlling the energizing circuit of said rotary magnet, and switches controlled by said master switch, as set forth.

39. In a-telephone system, a master switch provided with a private bank, a multiple terminal wiper for removing guarding potentials from the private bank contacts, a rotary switch, a rotary magnet, a wiper having a plurality of terminals for controlling the energizing circuit. of said rotary magnet, a rotary switch shaft for operating said wipers, said switch shaft adapted to be rotated by said rotary magnet, whereby the guarding-potential-controlling wiper may be properly operated, and trunk selectors governed in their operations by said master switch. i

40. In a telephone system, a trunk line, a ,rroup of subscribers lines provided with line terminals normally connected in mul tiple to said trunk line, means-by which any subscriber in the group may seize the trunk line for talking purposes, and automatic means for substituting a new trunk line for the idle subscribers each time a subscriber calls.

41. In a telephone system, a group of si'ibscribers lines, a group of trunk lines less in number than the subscribers lines, said subscribers lines provided with line terminals normally connected in multiple to an other group the preselected trunk line, and gutomatic means for substituting or selecting another idle trunk line each time a subscriber calls. 42. A telephone system comprising a group of subscribers lines, traveling terminals for said subscribers lines, an idle line to which saidv terminals are all normally connected in multiple, another group of sub scribers lines, necting said other group to said idle line, said connecting means including a switch having vertical motion to select groups and rotary motion to connect with the called line in the selected group.

43. A telephone system comprising a. group of subscribers lines, a step-by-stepactuated line wiper for eachsubscribe1"s line, an idle line, as many multiple terminals for said idle line as there are subscribers lines, each line wiper normally engagingone of the terminals of said idle line, another group of subscribers lines, and automatic means for connecting said other group to said idle line, said connecting means including a switch having vertical. motion to select groups and rotary motion to connect with the called line in the selected group. 44. A telephone system comprising a group of lines, traveling terminals for said lines, an idle line to which said terminals 9 are all normally connected in multiple, anof subscribers lines,-and automatic means for connecting said other group to said idle line, said connecting means including a switch having vertical motion to select groups and rotary motion to connect with the called line in the selected group.

45. A telephone system comprisinga group of lines, a step-by-step-actuated line, wiper for each line, an idle line, as many multiple terminals for said idle line as there are lines in said group, each line wiper normally engaging one of the terminals of said idle line, another group of subscribers lines, and automatic means for connecting said other group to said idle line, means including a switch having vertical motion to select groups and. rotary motion to connect with the called line in the selected group.

46. A telephone system comprising a said connecting means including a switch having vertical motion to select groups and and automatic means for con- 1 rotary motion to connect with the called line in the selected group.

47; A telephone system comprising a group of suscribers lines, a step-by-stepactuated line wiper for each subscribcrs line, an idle line, as many multiple terminals for said idle line as there are subscribers lines each line wiper normally engaging one ot the terminals of said idle line, said wipers being normally disconnected from the said group of lines, another group of subscribers lines, and automatic means for connecting said other group to said idle line, said connecting means including a switch having vertical motion to select groups and rotary motion to connect with the called line in the selected group.

48. A telephone system comprising a group ot lines, movable terminals for said lines, an idle line to which said terminals are all normally connected in multiple. said movable terminals being normally disconnected from the said group of lines, another group of subscribers lines, and automatic means for connecting said other group to said idle line, said connecting means including a switch having vertical motion to select groups and rotary motion to connect with the called line in the selected group.

all). A telephone system comprising a group of lines, a stcp-by-ste1 -actuated line wiper for each linm an idle line, as many multiple terminals for said idle iinc as there are lines in said group, each line wiper normally engaging one of the terminals of said idle line, said wipers being normally disconnected :from the said group of lin another group of subscribers lines, and automatic means for connecting said other group to said idle line, said connecting means including a switch having vertical motion to select groups and rotary motion to connect with the called line in the selected group.

50. A telephone system comprising a group of subscribers lines, movable terminals for said. subscribers lines, an idle line to which said terminals are all normally connected in multiple, said movable terminals being normally disconnected from the said group of lines, automatic auxiliary switches for closing connection between the lines of said group and their respective movable line terminals, another group of subscribers lines, and automatic means for connecting said. other group to said idle line, said connecting means including a switch having vertical motion to select groups and rotary motion to connect with the called line in the selected group.

51. A telephone system comprising. a group of subscribers lines, a step-bystepactuated line wiper for each subscribers line, an idle line, as many multiple terminals for said idle line as there are subscribers lines, each line wiper normally engaging one of the terminals of said idle line, said wipers being normally disconnected from the said group of lines automatic auxiliary switches for closing connection between the lines of said group and their respective wipers, another group otsubscribers lines, and automatic means for connecting said other group to said idle line said connecting means including a switch having vertical motion to select groups and rotary motion to connect with the called line in the selected group.

A telephone system comprising a group of lines, movable terminals for said lines, an idle line to which said terminals are all normally connected in multiple, said movable terminals being normally disconnected from the said group of lines, automati auxiliary switches for closing connection between the lines of said group and their respective movable line terminals, another group of subscribers lines, and automatic means for connecting said other group to said idle line, said connecting means ineluding a switch having vertical motion to select groups and rotary motion to connect with the called line in the selected group.

53. A telephone system comprising a group of lines, a step-by-step-actuated line wiper for each line, an idle line, as many multiple terminals for said. idle line as there are lines in said group, each line wiper normally engaging one of the terminals of said idle line, said wipers being normally disconnected from the said group of lines, automatic auxiliary switches for closing connection between the lines of said group and their respective wipers, another group of subscribers lines, and automatic means for connecting said other group to said idle line, said connecting means including a switch having vertical motion to select groups and rotary motion to connect with the called line in the selected group.

54. A telephone system comprisin a group of trunk lines for talking purpoi a'Ste-pliystep-operated line wiper normally connected with one oi said trunk lines, automatic means for advancing said wiper into connection with another trunk line when the said trunk line with which it is normally connected is put in use for talking purposes, another group of subscribers lines, and automatic means for connecting said other group to said trunk lines, said connecting means including a switch having vertical motion to select groups and rotary motion to connect with the called line in the selected group.

55. A telephone system comprising a group 0t trunk lines, multiple'terminals for said trunk lines arranged in banks, a line wiper for each bank of trunk'line terminals, said wipers all normally engaging multiple terminals of the same trunk line, automatic means for advancing all idle wipers to. another trunk line whenever one wiper is used for talking purposes, another group of subscribers lines, and automatic means for connecting said other group to said trunk lines, said connecting means including a switch having vertical motion to select groups and rotary. motion to connect with the called line in the selected group.

56. The combination of a subscribers telephone line, an idle trunk line, a normally closed switch intermediate of the two lines,

a normally open switch intermediate of the A rsubscribers line and thenormally closed switch, other lines terminating at said normally closed switch, another group of subscribers lines, and automatic means for connecting saidother group to said idle line,

said connecting means including a switch having vertical motion to select groups and rotary motion to connect with the called line in the selected group.

in engagement with the multiple contact of an idle trunk line, and electrically controlled means by which a calling subscrihers line'is connected to the idle trunk line without operating the wipersof the line switch allotted to the calling subscriber.

58. In a telephone system, a subscribers telephone, a line switch, a line terminating in said telephone-at the subscribers station,

and in said line-switch'at a central station,

a side switch allotted to said line switch, a-

private magnet for controlling said side switch, circuit controlling means at the sub-' scribers station for sending a preliminary impulse for energizing the said private mag net, a trunk line terminating in said line switch, a set of contacts for said trunk line, and wipers for said line switch normally in engagement with said trunk line, 'whereby when the subscriber sends in a preliminary impulse the private magnet is operated and the side switch'trippedand the line switch Wipers and trunk line connected to the subscribers line.

59. A telephone systemcomprising a plurality of subscribers lines, a line switch for each. line, a plurality of trunk lines common to all of the switches, automatic means whereby all except-one of said trunk' lines are normally maintained with guarding potential, automaticmeaiis whereby all line switches are normally in connection witln the unguarded trunk 11116, automatic means whereby if a line switch is operated the said unguarded trunk line is seized and made busy and the next idle trunk line deprived of guarding potential and all idle line switches advanced to the said next idleline.

60. A telephone system comprising a plurality of subscribers lines, a line switch 'for each line, a plurality of trunk lines common to all of the switches, a master switch allotted to said line switches, automatic means whereby all except one of the said trunk lines are normally maintained with guarding potential by the said master switch, automatic means whereby all line switches are normally in connection with the un uarded trunk line, automatic means where y if a vline switch is operated the unguarded trunk line ismade 'busy by. thesaid calling line switch and the next idle trunk line deprived of guarding potential by the-master switch and all idle line switches advanced to the said next idle line;

61. A telephone system comprising ,'subscribers lines, a line switch for every line, lines commonto the line-switches, a private wiper for each line switch, a side switch for each line switch having a first-and a second position, a rotary magnet for ea'ch line switch for operating the private wiper, automatic means whereby normally all the private wipers are maintained in connection with the same line, and automatic means wherebyone line switch may operate all the other line switches to cause their private wipers to be shifted while their side switches remain in first position. i

(32. Ina telephone system, a group ofsubscribers" lines, a group of trunk lines less 111 number than the subscribers lines, said subscribers lines pr'ovided with line terminals normally comu-cted 1,11 multiple to an idle and preselected one of said trunk'lines, au-

tomatig; meansby which anycallin'g subscriber temporarily excludes all other sub-.

scribersjrom the preselected trunkline, and automatic means for substituting or selectin'g another idle trunk line each time a sub-- scriber calls.

Signed by me at Chicago,'Cook county, Illinois, this 30th day of April, 1907.

' v v EDWARDD. FALES. W'itnesses:

,IIAumn'r'r M. Mmmmivr,

ARTHUR B. SPERRY. 

